Seed source wavelength broadband tuning device

Abstract

The invention discloses a seed source wavelength broadband tuning device which comprises a pump beam combiner, a gain fiber, a fiber isolator, a frequency conversion module and a laser output coupling module which are sequentially arranged on a fiber seed source laser output light path. A seed light wavelength monitoring module, a PID feedback circuit and a TEC module are sequentially connected between the optical fiber seed source and the frequency conversion module; according to the invention, the temperature of the frequency doubling crystal can be tuned in real time in the wavelength broadband tuning process of the seed source, so that the output power is not changed.

Description

Technical Field

[0001] The invention belongs to the field of laser technology, and in particular relates to a seed source wavelength broadband tuning device. Background Art

[0002] Rydberg atoms are of great significance to the field of atomic and molecular research due to their large atomic radius, long lifetime and high polarizability. The cascade two-photon excitation method of 852nm laser and 509nm laser can realize the Rydberg state of cesium atoms.

[0003] Among them, 852nm laser is generally directly output by semiconductor light source, while 509nm generally adopts frequency doubling technology, which is realized by frequency conversion of 1018nm seed source. Compared with 852nm semiconductor light source, wavelength tuning and temperature control of 509nm frequency doubling technology are relatively difficult. In addition to considering the seed source itself, temperature control of frequency doubling crystal must also be considered.

[0004] The temperature of the frequency conversion module affects the frequency doubling efficiency. Therefore, when the seed source wavelength changes, the required frequency doubling crystal temperature changes. If the crystal temperature does not change accordingly, the frequency doubling efficiency will decrease according to a certain rule, thereby affecting the final output power.

[0005] Frequency conversion modules usually use various types of frequency doubling crystals, which are temperature-sensitive devices. As the tuning of the front-end seed wavelength changes, the ambient temperature required by the frequency doubling crystal will also change. Summary of the invention

[0006] The object of the present invention is to provide a seed source wavelength broadband tuning device capable of tuning the temperature of a frequency doubling crystal in real time to achieve a constant output power.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a seed source wavelength broadband tuning device, including an optical fiber seed source for outputting a seed laser and a pump combiner for laser beam combining, which are sequentially arranged on the optical fiber seed source laser output optical path, a gain optical fiber for optical fiber power amplification, an optical fiber isolator for suppressing reverse reflected light, a frequency conversion module for optical frequency conversion, and a laser output coupling module for coupling spatial light shaping to the output in the optical fiber, wherein the pump combiner is connected to a pump source for generating pump light, and a seed light wavelength monitoring module for real-time monitoring of the wavelength of the optical fiber seed source and forming a corresponding voltage value change is sequentially connected between the optical fiber seed source and the frequency conversion module, and a voltage change and PI provided by the optical fiber isolator are used to monitor the wavelength of the optical fiber seed source in real time. The D circuit realizes the PID feedback circuit for real-time temperature feedback of wavelength changes and the TEC module for controlling the temperature of the frequency conversion module; the single-frequency laser output by the optical fiber seed source is combined with the high-power pump light generated by the pump source through the pump combiner into the same optical fiber and injected into the gain fiber, and the seed light power is amplified from 10mW to 10W using a multi-stage optical fiber MOPA optical path. After using an optical fiber isolator to ensure that there is no return light to damage the optical path, the high-power single-frequency laser is collimated and enters the frequency conversion module in the form of spatial light. The frequency is converted using the physical principles of various frequency conversion modules, and the spatial light with stable output power and frequency conversion is output under the stable temperature control of the TEC module, and then enters the laser output coupling module to realize the final optical fiber output.

[0008] Furthermore, the optical fiber seed source adopts a commonly used DFB single-frequency optical fiber laser seed source, which outputs a single-frequency laser of the order of 10 mW.

[0009] Furthermore, the gain optical fiber utilizes a multi-stage optical fiber MOPA optical path to amplify the seed light power from 10mW to the order of 10W.

[0010] Furthermore, when the wavelength of the seed laser output by the optical fiber seed source is modulated, the seed light wavelength monitoring module can quickly monitor the change in wavelength in real time. After the change is quantified into a voltage value, it is also fed back to the TEC module in real time through the PID feedback circuit. By adjusting the current output to the TEC module, the temperature of the frequency conversion module is quickly adjusted.

[0011] The beneficial effect of the present invention is that the present invention ensures that in the process of broadband tuning of the seed source wavelength, the temperature of the frequency doubling crystal can be tuned in real time to achieve a technology that the output power remains unchanged after frequency conversion. Under the premise of not affecting the single-frequency performance of the laser, the broadband tunability of the seed source wavelength is achieved, the optical path structure is not complicated, and the number of active optical devices is not increased, which can well meet the needs of practical applications.

[0012] In general, compared with the existing lasers using various frequency doubling conversion modules, the present invention has the characteristic of broadband tunable wavelength and does not add too many devices in the architecture. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention.

[0014] The figures are marked as follows: 1—optical fiber seed source, 2—pump combiner, 3—pump source, 4—gain fiber, 5—optical fiber isolator, 6—frequency conversion module, 7—laser output coupling module, 8—seed light wavelength monitoring module, 9—PID feedback circuit, 10—TEC module. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0016] Based on the needs of frequency doubling technology in various bands, the present invention proposes a tunable laser high-precision temperature-controlled seed source wavelength broadband tuning device, which involves high-precision temperature control technology and high-speed PID feedback technology of frequency-converted high-power laser under seed wavelength broadband tuning, especially for 509nm laser related applications used in Rydberg atoms.

[0017] Reference Figure 1 As shown, a seed source wavelength broadband tuning device disclosed in the present invention comprises an optical fiber seed source 1 for outputting a seed laser, and a pump combiner 2 for laser beam combining, which is sequentially arranged on the laser output optical path of the optical fiber seed source 1, a gain optical fiber 4 for optical fiber power amplification, an optical fiber isolator 5 for suppressing back-reflected light, a frequency conversion module 6 for optical frequency conversion, and a laser output coupling module 7 for coupling spatial light shaping to the output in the optical fiber, wherein the pump combiner 2 is connected to a pump source 3 for generating pump light, and a seed light wavelength monitoring module 8 for real-time monitoring the wavelength of the optical fiber seed source 1 and forming a corresponding voltage value change is sequentially connected between the optical fiber seed source 1 and the frequency conversion module 6, a PID feedback circuit 9 for realizing real-time temperature feedback for wavelength change by using the voltage change provided by the optical fiber isolator 5 and the PID circuit, and a TEC module 10 for controlling the temperature of the frequency conversion module 6.

[0018] The fiber seed source 1 adopts the commonly used DFB single-frequency fiber laser seed source, and the output single-frequency laser is combined with the high-power pump light generated by the pump source 3 through the pump combiner 2 into the same optical fiber and injected into the gain fiber 4. The seed light power is amplified from 10mW to 10W level by using the multi-stage optical fiber MOPA optical path. After using the optical fiber isolator 5 to ensure that there is no return light to damage the optical path, the high-power single-frequency laser is collimated and enters the frequency conversion module 6 in the form of spatial light. The frequency is converted using the physical principles of various frequency conversion modules 6. Under the stable temperature control of the TEC module 10, the output power is stable and the spatial light after frequency conversion enters the laser output coupling module 7 to realize the final optical fiber output.

[0019] When the wavelength of the optical fiber seed source 1 is modulated, the seed light wavelength monitoring module 8 can monitor the change of the wavelength in real time and quickly. After the change is quantified into a voltage value, it is also fed back to the TEC module 10 in real time through the PID feedback circuit 9. By adjusting the current output to the TEC module 10, the temperature of the frequency conversion module 6 is quickly adjusted. Through rapid PID negative feedback, the change of the temperature of the frequency conversion module 6 corresponding to the seed wavelength modulation amount is achieved. The reduction in frequency doubling efficiency caused by the change in the wavelength of the front-end seed source is offset by the temperature change of the frequency conversion module 6, so that the frequency doubling efficiency remains unchanged, thereby ensuring the unchanged output power.

[0020] The present invention realizes the change of the seed wavelength modulation amount corresponding to the temperature of the frequency conversion module 6 through rapid PID negative feedback. The reduction of the frequency doubling efficiency caused by the change of the laser wavelength of the front-end optical fiber seed source 1 is offset by the temperature change of the frequency conversion module 6, so that the frequency doubling efficiency remains unchanged, thereby ensuring the unchanged output power.

[0021] The above embodiments are only illustrative of the principles and effects of the present invention, as well as some embodiments of its application. For those skilled in the art, several modifications and improvements may be made without departing from the creative concept of the present invention, and all of these belong to the protection scope of the present invention.

Claims

1. A seed source wavelength broadband tuning device, characterized in that: The invention comprises an optical fiber seed source (1), a pump beam combiner (2), a gain optical fiber (4), an optical fiber isolator (5), a frequency conversion module (6) and a laser output coupling module (7) which are sequentially arranged on the laser output optical path of the optical fiber seed source (1); the pump beam combiner (2) is connected to the pump source (3); a seed light wavelength monitoring module (8), a PID feedback circuit (9) and a TEC module (10) for controlling the temperature of the frequency conversion module (6) are sequentially connected between the optical fiber seed source (1) and the frequency conversion module (6); the single-frequency laser output by the optical fiber seed source (1) is combined with the high-power pump light generated by the pump source (3) through the pump beam combiner (2) into the same optical fiber and injected into the gain optical fiber (4); after passing through the optical fiber isolator (5), the high-power single-frequency laser enters the frequency conversion module (6) in the form of spatial light for frequency conversion; the spatial light with stable output power and frequency conversion is output under the temperature control of the TEC module (10) and then enters the laser output coupling module (7) to realize the final optical fiber output.

2. A seed source wavelength broadband tuning device according to claim 1, characterized in that: The optical fiber seed source (1) adopts a DFB single-frequency optical fiber laser seed source, which outputs a single-frequency laser of the order of 10 mW.

3. The seed source wavelength broadband tuning device according to claim 1, characterized in that: The gain optical fiber (4) utilizes a multi-stage optical fiber MOPA optical path to amplify the seed light power from 10 mW to the order of 10 W.

4. A seed source wavelength broadband tuning device according to claim 1, 2 or 3, characterized in that: When the wavelength of the seed laser output by the optical fiber seed source (1) is modulated, the seed light wavelength monitoring module (8) monitors the wavelength change in real time and feeds back the change to the TEC module (10) in real time through the PID feedback circuit (9), thereby adjusting the temperature of the frequency conversion module (6).

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